N922BA

HISTORY OF FLIGHTOn November 7, 2017, about 1204 eastern standard time, an Icon Aircraft A5 special light sport amphibious airplane, N922BA, sustained substantial damage when it was involved in an accident near Clearwater, Florida. The private pilot sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.

The airplane departed from Island Ford Lake in Odessa, Florida, about 1147. According to data from the Icon digital to analog (DAC) data memory unit that was installed on the airplane, the airplane climbed to a GPS altitude of 1,909 ft and proceeded north for 4 nautical miles (nm) before turning west toward the Gulf of Mexico. The airplane then flew for 10 nm at a GPS altitude of about 600 ft and descended over the gulf before turning south. During the final 3 minutes of the flight, the airplane was traveling in a southerly direction along the shoreline; figure 1 shows the flight track. During the last 2.5 minutes of the flight, the pilot conducted three maneuvers with high angles of attack (AOA) and load factors of almost 2 Gs; at that time, the airplane was over the water at GPS altitudes between 0 and 358 ft. During the final maneuver of the flight, the airplane entered a right turn, the engine power decreased, and the AOA reached 16°. The last recorded data point, at 1203:41, showed that the airplane's airspeed was 75 knots and heading was 354°.

Figure 1. Last 3 minutes of GPS flight track.

The airplane was also equipped with a Rotax engine control unit. The last recorded data point, at 1203:43, indicated an engine speed of 2,829 rpm and a throttle position of 27%.

Multiple witnesses in the area stated that they saw the airplane flying very low, between 5 and 300 ft, over the water as the airplane maneuvered south close to the shoreline. Some witnesses reported that the airplane was making steep turns and high-pitch climbs up to about 500 ft and that the engine sounded normal. A witness provided an image of the airplane over the water, as shown in figure 2. A commercial fisherman stated that the airplane flew over his vessel at an altitude that was less than 300 ft. Another commercial fisherman, who was located about 900 ft north of the accident site, stated that he observed the airplane flying from the north "really close" to houses. The airplane then flew south past his position, descended briefly, and climbed. After entering a steep climb, the airplane descended on an easterly heading in a steep nose-down attitude; the airplane's pitch attitude decreased as the airplane continued to descend. The witness reported that the airplane impacted the water in a 45° nose-down, wings-level attitude.

Figure 2. Still image of the accident airplane just before the crash (Courtesy of Mr. Fred Grunden.) PERSONNEL INFORMATIONThe pilot had 14.5 hours of total flight experience in the accident airplane. The pilot made an entry into his logbook indicating that, while en route from the Peter O. Knight Airport in Tampa, Florida, to his home, he flew under the Skyway Bridge; the bridge has a 180-ft vertical clearance over the water. Recovered GPS data showed that the pilot flew under the bridge on October 26, 2017. A few days later, the pilot stated on social media, "flying the Icon A5 over the water is like flying a fighter jet!" AIRCRAFT INFORMATIONThe pilot accepted delivery of the airplane about 4 weeks before the accident. The airplane was equipped with an AOA indicator and a ballistic complete aircraft parachute (CAP) system.

The Icon A5/Pilot's Operating Handbook, section 2.7, indicated that the design maneuvering limits with flaps 0° and an airplane weight of 1,510 pounds were +4 and -2 G. (The accident airplane's takeoff weight was estimated to be 1,476 pounds.)

Section 2.16 stated that "there are no restrictions on the use of the CAP system. Optimal CAP actuation is from level flight above 500 ft AGL [above ground level]." Section 3.19 provided the following emergency procedures for a loss of control:

1. CAP Handle – PULL HARD

2. Ignition Key – OFF

Section 4.3 showed the After Cockpit Entry checklist, which included a step to remove and stow the CAP safety pin so that the pilot could activate the system quickly if necessary.

Section 7.2.1 stated the following:

A5 incorporates numerous features to help control the dynamics of stall and improve spin resistance, including blended wing shapes, stall strips and wing cuffs. Stall characteristics depend on a number of factors, the most important being rate of stall onset, which can affect the dynamics of stall progression along the span. The A5 remains controllable throughout these various stall progressions up to 30° bank angles, even when fully stalled.

Section 7.6.2 stated that the airplane's AOA system works "by using static ports to measure the difference in pressure from the top and bottom of the left wing near the leading edge. These values are compared and computed to drive the AOA indicator electronically." The section also stated that "the AOA gauge provides a visual indication of how hard the wing is working to generate lift and how much more lift it can supply at any given time." The face of the AOA gauge incorporates green, yellow, and red bands, as shown in figure 3, to indicate the available lift margin above stall. The Icon Sport Flying Academics manual indicated that, at the lower green band, the wing is not working hard, and lift forces are generated mostly by airspeed. The yellow band signifies that the wing is working harder (taking "a bigger bite" from the airflow); at the top of the yellow band, the wing will begin to stall. The red band begins at 15.6°, which is also shown in figure 3, and signifies an aerodynamic stall, at which point lift would begin to degrade.

Figure 3. AOA information from the Icon Sport Flying Academics information.

The A5 Sport Flying Operations manual discussed energy management as part of the low-altitude considerations section. The energy management discussion stated the following:

Recall that our energy state at any given time is defined by our altitude and airspeed. So at low altitudes our energy is determined almost completely by our airspeed. If we get slow at higher altitudes, we can just push over and trade altitude for airspeed. At low altitude the throttle is our only tool for maintaining or adding energy to our airplane. We said during our discussion of turn performance that 60-75 KIAS [knots indicated airspeed] was the sweet spot for maneuvering the A5, and this holds true at low altitude as well. Much below 60 KIAS we find ourselves at relatively low energy. The aircraft remains controllable but will be more sluggish and less responsive to our control inputs. Lower speed also means less stall margin – meaning our AOA is high and approaching aerodynamic stall. AIRPORT INFORMATIONThe pilot accepted delivery of the airplane about 4 weeks before the accident. The airplane was equipped with an AOA indicator and a ballistic complete aircraft parachute (CAP) system.

The Icon A5/Pilot's Operating Handbook, section 2.7, indicated that the design maneuvering limits with flaps 0° and an airplane weight of 1,510 pounds were +4 and -2 G. (The accident airplane's takeoff weight was estimated to be 1,476 pounds.)

Section 2.16 stated that "there are no restrictions on the use of the CAP system. Optimal CAP actuation is from level flight above 500 ft AGL [above ground level]." Section 3.19 provided the following emergency procedures for a loss of control:

1. CAP Handle – PULL HARD

2. Ignition Key – OFF

Section 4.3 showed the After Cockpit Entry checklist, which included a step to remove and stow the CAP safety pin so that the pilot could activate the system quickly if necessary.

Section 7.2.1 stated the following:

A5 incorporates numerous features to help control the dynamics of stall and improve spin resistance, including blended wing shapes, stall strips and wing cuffs. Stall characteristics depend on a number of factors, the most important being rate of stall onset, which can affect the dynamics of stall progression along the span. The A5 remains controllable throughout these various stall progressions up to 30° bank angles, even when fully stalled.

Section 7.6.2 stated that the airplane's AOA system works "by using static ports to measure the difference in pressure from the top and bottom of the left wing near the leading edge. These values are compared and computed to drive the AOA indicator electronically." The section also stated that "the AOA gauge provides a visual indication of how hard the wing is working to generate lift and how much more lift it can supply at any given time." The face of the AOA gauge incorporates green, yellow, and red bands, as shown in figure 3, to indicate the available lift margin above stall. The Icon Sport Flying Academics manual indicated that, at the lower green band, the wing is not working hard, and lift forces are generated mostly by airspeed. The yellow band signifies that the wing is working harder (taking "a bigger bite" from the airflow); at the top of the yellow band, the wing will begin to stall. The red band begins at 15.6°, which is also shown in figure 3, and signifies an aerodynamic stall, at which point lift would begin to degrade.

Figure 3. AOA information from the Icon Sport Flying Academics information.

The A5 Sport Flying Operations manual discussed energy management as part of the low-altitude considerations section. The energy management discussion stated the following:

Recall that our energy state at any given time is defined by our altitude and airspeed. So at low altitudes our energy is determined almost completely by our airspeed. If we get slow at higher altitudes, we can just push over and trade altitude for airspeed. At low altitude the throttle is our only tool for maintaining or adding energy to our airplane. We said during our discussion of tu...